The 3,611-lb. capacity fuel system uses mainly fuel bladders in the outboard and inboard wings and engine nacelles, along with left and right outboard wet wing tanks. The main system holds 2,546 lb. and the inboard aux tanks hold 1,065 lb. The aircraft may be fitted with additional, external nacelle tanks, in place of the Raisbeck wing lockers, thereby increasing total fuel capacity by 1,581 lb.
The tricycle landing gear has a single nosewheel and dual main wheels. A 28-VDC electric power pack provides hydraulic pressure for landing gear extension and retraction. In the event of power pack failure, a hand hydraulic pump enables the crew to extend the landing gear. The hydraulic fluid reservoir has a low fluid level warning function. A separate, unpowered hydraulic system is used for the wheel brakes. Engine bleed air is used for brake deicing.
Left and right engine bleed air, pre–cooled through heat exchangers in the inboard wing sections, is used for cabin pressurization, engine inlet anti-ice protection, wing and horizontal stabilizer leading edge deice protection, window defogging and brake deicing. The 6.5-psi pressurization system provides a 10,380-ft. cabin altitude at the aircraft's FL 350 maximum cruising altitude. Pressurization is manually set by a controller in the instrument panel and controlled by normal and safety outflow valves in the rear pressure bulkhead. A 115-cu.-ft. oxygen bottle supplies quick-donning masks in the cockpit and individual passenger drop-down oxygen masks.
The dual-zone climate control system uses engine bleed air for heating. It also has an electric heating system that can be powered by a ground power cart prior to engine start. Air-conditioning, though, only is available when the right engine is running because it drives the vapor cycle machine's compressor.
Occupants enter the aircraft through an aft, left-side 4.3-ft.-high-by-2.2-ft.-wide air-stair door that has passenger assist hand cables on the left and right. The aircraft also is available with a 4.1-ft.-high-by-4.3-ft.-wide cargo door. The aft lavatory is immediately across from the entry door. It features an internally serviced flush toilet, a window and optional, foldout vanity with wet sink, mirrors and storage racks. Aft of the lavatory is a 55-cu.-ft., internally accessible baggage compartment. If the lav features the optional foldout vanity, baggage compartment capacity is reduced to 45 cu. ft. Raisbeck Engineering wing lockers add 16 cu. ft. and 600 lb. of external baggage capacity.
The 350i features a new sound suppression system featuring triple-layer skin panel insulation and dynamically tuned vibration dampers, plus 3-in.-thick thermal insulation and an acoustically isolated interior shell. The system is tuned for 1,500 prop rpm and it lowers noise to about 78 dB in cruise, a 4-dB reduction.
The main seating area is 4.8 ft. high, 4.5 ft. wide and 13.9 ft. long, providing about 248 cu. ft. of volume for the passengers. The fuselage has a square oval cross section and a flat floor, except for a small rise in the front to accommodate the center section wing spar. Thus, it has more usable foot, hip, shoulder and headroom than the raw dimensions might suggest.
There are seven windows on each side of the main seating area. Similar to those on the Boeing 787, each window has an electro-chromic darkening pane.
Most King Air 350i aircraft are con–figured with fore and aft double-club seating accommodating eight passengers. One or both forward facing chairs in the aft cabin can be swapped temporarily or permanently for optional ottoman leg rests. Individual seat warmers are avail–able as options. Cargo/combi, 15-occupant high-density seating, air ambulance and special mission versions also are available.